"The data at hand indicate that the electrically excited laser dye-doped organic semiconductor yields a highly directional, spatially coherent, nearly diffraction-limited beam with characteristics normally associated with narrow-linewidth dye lasers. The estimated linewidth of the emission is comparable with the linewidth reported for broadband laser emission in pulsed dye lasers." [Opt. Lett. 31, 412-414 (2007).]
"Examination of available results indicates that there is sufficient evidence to classify the reported emission as being equivalent to broadband dye laser radiation... In the spectral domain the high visibility of the interferograms, V ~ 0.9, is a macroscopic manifestation that the measured radiation exhibits much higher coherence than the coherence associated with ASE. Also, the visibility of the observed interferograms is nicely within range of the visibility previously measured, using two-slit interferometry, for soft X-ray laser emission and approaches the visibility (V ~ 0.95) for the 3s2-3p10 transition of a He-Ne laser." [Appl. Phys. B 90, 101-108 (2008).]
The search for the electrically-excited organic laser has a long history. These papers report on the first successful observation of coherent emission from organic semiconductors using electrical excitation (or electrical pumping). The gain medium in these interferometric emitters is the laser dye coumarin 545 tetramethyl. The coherent emission is generated in a miniature, sub micrometer, resonator. The emission beam is nearly diffraction limited and the spectral linewidth has been determined, using interferometric means, to be ~ 11 nm which approximates the linewidths available from broadband dye lasers. Thus, the spatial and spectral coherence characterictics, from these pulsed interferometric emitters, are indistinguishable from broad-band dye laser emission. Note: the organic semiconductors used in these experiments are tandem organic light-emitting diodes also known as tandem oleds.
Key words: coherent OLED, coherent tandem OLED, coherent OLED emission, coherent organic semiconductor, electrical excitation, electric organic laser, electrical organic laser, electrical pumping, electrically excited organic laser, electrically pumped organic laser, electrically pumped dye laser, laser OLED emission, organic laser emission
Published on the 23rd of June, 2008.
Updated on the 27th of March, 2018.